Electrical arcs can sometimes form within a plasma processing chamber and cause damage to the substrate or the chamber or can deposit particles that cause defects in a substrate. Mitigation techniques often involve shunting power away from the chamber until an arc is extinguished. While power is diverted from the chamber processing efficiency decreases, and thus quickly returning the power level to steady state is desired. At the same time, the plasma, chamber, and other elements cool while power is diverted, and thus processing efficiency does not return to steady state until these temperatures return to steady state. Thus, arc mitigation via power diversion reduces processing efficiency and throughput.
Yet, shunt time cannot be too short since arcs can flare back up or spawn new arcs if power returns before the arc is sufficiently extinguished. Since arcs decay at different rates, many techniques select a fixed shunt period that is long enough to allow all arcs to dampen to a state where it is safe to open the shunt and resume power delivery to the chamber. Yet, by fixing the shunt time according to the slowest arc decay rate, power is often shunted longer than necessary for arcs that quickly decay.